Polyurethanes of polyalkylene etherthioether glycols



Uit

POLYURETHANES F POLYALKYLENE ETHER- THIQETHER GLYCOLS Frederic B. Stiimar, Wilmington, DeL, assignor to E. I. du Pent tie Nernours and Company, Del, a corporation of Delaware No Drawing. Application May 23, 1956 Serial No. 586,650

14 Claims. (Cl. 260-77.5)

active hydrogen compounds, to produce elastomers, but

some of these are deficient in their resistance to swelling on extended contact with water or organic solvents. Caulking and sealing compounds obtained by condensation of certain thioplasts with organic diisocyanates are known but these compounds do not exhibit good elasticity.

An object of the present invention is to provide condensation polymers which exhibit good elasticity and resistance to the swelling effects of Water and aliphatic hydrocaubon solvents. A further object is to provide highly useful elastomers from polyalkylene ether-thioether glycols. Another object is the provision of elastomers with improved low temperature properties. Other objects will appear as the description of the invention proceeds.

These and other objects of the following invention are accomplished by reactions involving a polyalkylene etherthioether glycol having a molecular weight of at least 750, an organic diisocyanate and a chain-extending agent.

The term, polyalkylene ether-thioether glycol as used throughout the specification and claims refers to compounds containing terminal hydroxyl groups having both ether and thioether linkages between alkylene radicals in the molecule. These compounds may be represented by the formula, HO{-G-Xr H, wherein G is an alkylene radical having from 1 to 10 carbon atoms and X represents both oxygen and sulfur with the terminal X being oxygen, and p is an integer greater than 1. In the polyether-thioethers useful in this invention, 2 is sufficiently large that the glycol has a molecular weight of at least 750. In these glycols, not all of the alkylene radicals present need be the same. Typical of the numerous polyalkylene ether-thioether glycols which may be used are:

These glycols may be made by azeotropically distilling water from a mixture of a thioether glycol in which both hydroxyl groups are [3 to a sulfur atom and a glycol or glycol ether in the presence of a catalyst such as ptoluene sulfonic acid. The preparation of such polyalkylene ether-thioether glycols by this method is well known in the art. The sulfur content may be increased 0 aten as the proportion of the thioether glycol increases. When thiodiglycol, HOC H SC H OH, is condensed with itself by this method, there is one sulfur and one oxygen in the repeating unit. Alternatively, bis-halogenothioethers may be reacted with the alkali salts of the glycols. Glycols with more than one sulfur may be used, for example, HOCgH4SC4HgSC2H4OH may be made by condensing 1 mol of ClCH CH CH CH Cl with two mols of HOC 'H SNa. This may then be condensed with itself or other glycols. When condensed with itself, the repeating unit has two sulfur and one oxygen units. By these methods of preparation, the terminal groups of these pols alkylene ether-thioether glycols are always hydroxyl groups. By suitable choice of glycols and thioglycols, the ratio of oxygen to sulfur may be varied widely. Polyalkylene ether glycols of higher molecular weight may be used, for example, a polytetramethylene ether glycol of molecular weight about 1000 can be condensed with the sulfur intermediate to give a polyalkylene etherthioether glycol of molecular weight about 3000. A preferred range lies from about one oxygen to one sulfur to about fifteen oxygens to one sulfur. With higher proportions of sulfur, the polymers tend toward the plastic and with lower proportions of sulfur, the improvement in solvent-resistance and freeze-resistance due to the presence of the thioether group decreases. For purposes of the present invention, the polyalkylene ether-thioether glycols which may be used should have a molecular weight of from 750 to about 10,000. The molecular weights referred to herein are calculated from the hydroxyl numbers of the glycols and, therefore, represent number average values.

Any of a wide variety of diisocyanates may be employed to react with the polyalkylene ether thioether glycols, including aromatic, aliphatic and cycloaliphatic diisocyanates and combinations of these types. Representative compounds include toluene-2,4-diisocyanate, mphenylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4,4 biphenylene diisocyanate, 1,5-naphthylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-thexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4-methylene-bis-(cyclohexyl isocyanate) and 1,5-tetrahydronap'hthylene diisocyanate. Arylene diisocyanates, i.e., those in which each of the two isocyanate groups is attached directly to an aromatic ring, are preferred. In general, they react more rapidly with the polyalkylene ether-thioether 'glycols than do the alkylene diisocyanates. Compounds such as toluene-2,4-diisocyanate in which the two isocyanate groups differ in reactivity are particularly desirable. The, diisocyanates may contain other substituents, although those which are free from reactive group other than the two isocyanate groups are ordinarily preferred. In the case of the aromatic compounds, the isocyanate groups may be attached either to the same or to different rings. Dimers of the monomeric diisocyanates and di(isocy anatoaryl) ureas such as di(3-isocyanato-p-tolyl) urea, may be used. I

The chain extending agentwhich is used in the preparation of the new elastorners of this invention is a compound containing a plurality of active hydrogen atomscapable of reacting with isocyanates, no more than two atoms in the molecule having active hydrogen attached thereto. Water is the cheapest and, in many cases, the most desirable chain extending agent. Hydrogen sulfide is another inorganic compound useful for this purpose.

There may also be employed organic compounds containing two and only two atoms in the molecule to which are attached active hydrogen atoms. The termfactive' hydrogen atoms refers to hydrogens which,

their position in the molecule, display activity according to the Zerewitinoff test as described by Kohler in J. Am, 7 I

7 2,900,368 I n 3 a 4 Chem. Soc. 49, 3181 (1927). In the chain extenders usechain extended, it forms a tough, rubbery clump which ful in this invention, the active hydrogen atoms are atbegins to pull away from the mixer and which may then tached to oxygen, nitrogen or sulfur; The groups conbe removed from the mixer and worked on a rubber mill taining the active hydrogen will ordinarily be -OH, to form a smooth band. The amount of chain extending .SH,rNH-, NH COOH, CONH CONI-IR 5 agent which is used is not critical. An amount less than where R represents an organic radical, -SO OH, that theoretically required to react with all of the SO NH or-CSNHQ The chain extending compound isocyanate groups of both the isocyanate-tenninated polymay be aliphatic, aromatic or cycloaliphatic or of mixed met and any free unreacted diisocyanate which may be type. Typical of many organic compounds which are present may be used, in which case, the resulting elastomer useful in this connection are ethylene glycol," hexwill have free isocyanate groups. In this case, the elasamethylene glycol, diethylene glycol, adipic acid, tertomer may be molded and cured directly or may be staephthalie acid, adipamide, LZ-ethanedithjol, hydrobilized against premature curing by the addition of small quinone, monoethanolamine, 4-amino-benzoic acid, mamounts of a nitrogen base containing at least one hydrophenylenediamine, propylenediamine, 4-aminobenzamide, gen atom attached to nitrogen. When stabilized in this sulfanilamide, aminopropionic acid, 1,4-cyclohexanedisulmanner, the reaction product may be stored for extended fonamide, 1,3-propanedisulfonamide, 4-hydroxybenzoic periods before curing. If an amount of chain extending a id, -ami o hen l, ethyl ediamj e, n i i a id, u agent is used which is equivalent to that theoretically recinamide, 1,4-butanedisulfonamide, 2,4-tolylenediamine, quired t ea w all of the isocyanate g ps or if an 'bis(4-aminophenyl) methane, fl-hydroxypropionic acid excess over this amount is used, the resulting reaction and 1,2-efl a dim1f i ii CQmp undg nt i i at product will be stable and will not cure until an additional least one amino group are the preferred'organic chain 0r i'liisocyaflfite Or other Curing agent is added- 111 extending agents. It is to be understood that'for purposes y event, the amount of chain extending agent and molar of the present invention, these organic compounds may ratio of organic diisocyante -to the polyalkylene etherbe used either singly or-in combination, or in combination thioether glycol used should be selected so that the resiwith water dues resulting from the glycol comprise at least 35% of The elastomeric products of the presentinvention may the total weight of the product. be prepared by several general procedures. In one meth- AS InenfiOnBd above, the isocyallate-tefminated P 3- od, a molar ex e f an organic dijsgcyanate i i ed mer is reacted with the chain extending agents containing with the pglyalkylene th -thio th r glycol i itabl active hydrogen. The reactions of isocyanates with the mixi equipment t a temperature whi h i referably active hydrogen containing groups present in the various from 70-120 C. but which may range from about typical chain extending agents are described in the litera- 50150 C. The molar ratio of diisocyanate to glycol is tllre as Proceeding as fOHOWSI preferably between 1.1:1 and 12:1. If themolar ratio of diisocyanate to glycol is close to unity or when the Niall-CO2? molecular weight of the g1 col is very hig the reaction 2 a H CO NH +008? m b Y d h t U NCO+HOR- NH-CO-O-R- ass may ecome qui e v1scous an u ynux n equipment may be required. Accordingly, the reaction may be carried out m a Werner-Pflerderer m xer. The resulting product at this stage of the reactlon 1s a linear intermediate isocyanate-terminated polymer containing urethane linkages The product may be represented by NH CO NH CO R 7 It is apparent from the foregoing table that when water wherein B is a bivalent organic radical which is derived and hydrogen s d are used as chain extenders, e e is from the organic diisocyanate and is, therefore, inert to arb0ny1 lmkmg group between the imino groups, which isocyanate groups; O. G O is a bivalent radical resultunino groups are attached to the isocyanate residues. ing fr removal f the terminal hydrogen atoms f When the other typical chain extenders are used, an acyl a l lk l th thj th glycol; and n is an integer radical 1s attached to the imino group. Thus, when these greater h Zara wi h a molar i f diisocyanate other typical chain extenders react with two free isocyato glycol of 2:1, It in the above formula is 1; however, Bate Q P of the isocyanate4erminated P y Units as the molar ratio of diisocyanate to glycol approaches if Present, molecules of the Original dl'iswyanate, a unity, n ill b a very large b wi h molar Tatios diacyl radical is the connecting radical between the imino of dji to l l exceeding 2;1 there ill, f groups which are attached to the isocyanate residues. b some umeacted dii t left i h These diacyl radicals are hereinafter referred to by the tion mixture. letter Q This isocyanate-terminated polymer may then be re- After reaction of the chain extending agents with the acted with a chain extending agent so as to provide highisocyallate-tel'millated P y and y eXCeSS diiSO- 1 f 1 l t Th h i xt di g agent S rv 'cyanate which may be present, the resulting product is a to link the isocyanate-terminated polymer units together polymer consisting essentially of structural units having so as to lengthen the polymer chain and also to provide the formula r ii i -NHB- G-OGOO-NIE[ B NH HNB-NH active hydrogen atoms which serve as potential curing or wherein OG-O is a bivalent radical resulting from cross-linking sites. This reaction of the chain extending removal of the terminal hydrogen atoms from a polyagent with the isocyanate-terminated polymer may be alkylene etherthioether glycol; B is a bivalent organic carried out in heavy-duty mixing equipment, such as a radical; Q is a radical selected from the group consisting Werner-Pfleiderer mixer at temperatures of from about of a carbonyl radical and a diacyl radical; nis an integer 70-150? C. As the isocyanate-terminated polymer is greater than zero; and m is an integer including zero;

each of the said structural units being connected to the 4 next by a radical Q, having the significance defined above.

The product which is obtained after reaction of the isocyanate-terminated polymer with the chain extending agent may be cured to provide a highly useful elastomer. If all of the isocyanate groups have been reacted with the chain extending agent, the polymer may be cured by the addition of a curing agent such as an organic diisocyanate. Representative compounds which may be used include toluene-2,4-diisocyanate, the dimer of toluene-2,4-diisocyanate, 4,4'-methylenedi-o-tolylisocyanate and 1,3-bis(3isocyanato-4-methylphenyl) urea. In the curing of these elastomers from about 1 to 20 parts of curing agent per 100 parts of polymer is suflicient at temperatures of about 100-150 C.

While the preparation of the highly useful elastomers of the present invention has been described by the reactions of a molar excess of'an organic diisocyanate with a polyalkylene ether-thioether glycol, followed by reaction with a chain extending agent, it is to be understood that these elastomers may be prepared by adding all of the reactants at once. Alternatively, the chain extender may first be reacted with the organic diisocy-anate and this reaction product be mixed with either the polyalkylene ether-thioether glycol or the reaction product of the glycol with additional organic diisocyanate. It is also to be understood that the elastomeric reaction products of the present invention may be prepared by first reacting the polyalkyleneether-thioether glycol with phosgene to form a bischolorformate ester and then reacting this product with an organic diamine and additional phosgene to produce the desired elastomer.

When the elastomeric reaction products of the present invention are prepared by first reacting a molar excess of an organic diisocyanate With a polyalkylene etherthioether glycol, this reaction may be controlled by the presence of small amounts of an acid reacting compound, such as an acid chloride. When the resulting isocyanateterminated polymer is reacted with a chain extending agent, the reaction may be accelerated by the presence of the acid salt of an organic tertiary nitrogen or phosphorus base.

The following examples will better illustrate the nature of the present invention; however, the invention is not intended to be limited to these examples. Parts are by weight unless otherwise indicated.

Example 1 to 150 C. at 1 mm. pressure. The molecular weight of the glycol thus obtained was 1500 as calculated from the-hydroxyl number of 73.7.

90 parts of the glycol thus obtained and 60 parts of toluene-2,4-diisocyanate were mixed and heated at 100 C. for thirty minutes. The reaction mixture was then transferred to a Werner-Pileiderer mixer and 1 part of pyridine was added followed by 6.3 parts of water. After mixing at 100 C. for 30 minutes, a waxy crumb resulted. This was removed from the mixer and cured in a press at 130 C. under pressure for 30 minutes. A smooth amber slab was obtained which showed a tensile strength of 3000 lbs. per sq. in., an elongation at the break of 105%, a volume swell after 7 days of exposure at room temperature in water of 1.28% and in N-hexane of 1.42%. Bureau of Standards abrasion test was 119%.

Example A polymeric glycol containing repeating units of the structure --[CH CH SCH CH O] terminated in OH groups was prepared by azeotropically distilling the following charge: 488 parts of thiodiglycol, parts toluene, 17 parts p-toluene sulfonic acid. After 70 parts of water had been removed, the product was isolated and dried by the procedure described in Example 1. The yield of waxy glycol was 184 g. which had a hydroxyl number of 33. The molecular weight was calculated from this to be 3360. Analysis showed 29.9% sulfur.

50 parts of the glycol thus prepared was mixed with 25 parts of toluene-2,4-diisocyanate and 0.1 part of ptoluene s'ulfonyl chloride and heated to C. for 30 minutes. To the mass was then added 0.4 part of pyridine and 2.5 parts of water with stirring and the viscous syrup was heated at 80 C. for a further /2 hour. The resulting plastic mass was sheeted on a rubber mill and formed a smooth band. It was then cured in a press at 130 C. for 30 minutes under pressure. An eleastomeric plastic of the following properties was obtained: tensile strength, 1400 lbs. per sq. in.; elongation at the break, 100%.

Example 3 A polymeric glycol containing repeating units of the Structure tenninated in OH groups was prepared by azeotropically distilling the following charge: 305 parts thiodiglycol, 155 parts ethylene glycol, 90 parts toluene, 18 parts p-toluene sulfonic acid. After parts of water had been removed, the product was isolated and dried by the procedure of Example 1. The yield of glycol was 105 parts. The hydroxyl number was 21.6 which indicated a molecular weight of 5200. The percent sulfur was. 22.6.

91 parts of the glycol thus prepared was mixed with 40 parts of toluene-2,4-diisocyanate and heated to 100 C. for 1 hour. The charge was then transferred to a Werner-Pfleiderer mixer. To it were added 0.8 part of pyridine and 4.2 parts of water. Milling was continued at about 80-85 C. After 40 minutes, a Waxy crumb formed. The crumb was removed from the mixer and milled on a rubber mill to form a smooth sheet. This material was then put in a press and cured for 30 minutes at C. to give an amber slab which had a tensile strength of 2000 lbs. per sq. in. and an elongation at the break of 300%. It had only a negligible swelling after immersion in water for 4 days.

Example 4 A polymeric glycol containing repeating units of the structure terminated in OH groups was prepared by azeotropically distilling the following charge: 305 parts thiodiglycol, 263 parts diethylene glycol, parts toluene, 17 parts p-toluene sulfonic acid. After 86 parts of water had been removed, the product was isolated and dried by the same procedure as in Example 1. The yield was 242 parts of a glycol with a hydroxyl number of 33.8 which gave a'calculated molecular weight of 3300. The analysis for sulfur was 17.2%

50 parts of the polyethylene ether-thioether glycol thus prepared was mixed with 26 parts of toluene-2,4-diisocyanate and 0.2 partof p-toluene sulfonyl chloride and heated at 100-1'10 C. for 2 hours. Then 0.5 part of pyridine and 2.7 parts of 'water were added and the charge was heated at 80C. for 15 'minutes, The prodnot was then sheeted out on a rubber mill: to "forma smooth band. This was then placed in a press and'cured at 130 C. under pressure for 30 minutes. The elastomer 'had the-following properties: tensile strength, ,3500lbs.

per sq. in. elongation at the break-500%.

7 EWPW A polymeric' glycol having repeating units of the following structure H p -rcH.c z H2 H2"I V r CH OCH CH OCH CH O] terminated in -OH groups Wasprepared by azeotropic distillation of. the following charge: 305 partsthiQ EIycol, 375 parts triethylene glycol, 150 parts toluene, 17 parts p-toluene sulfonic acid. After 87 parts of water had been'removed, the product was isolated and dried by the same procedure as in Example 1. The yield was 98 parts of a glycol having a hydroxyl number of 33.1 which indicated a molecular weight of 3400. The percent sulfur in the product was 13.5.

90 parts of the glycol thus prepared and 45 parts of toluene-2,4-diisocyanate were mixed and heated to 100 C. for 2 hours. There were then added 1 part of pyridine and 4.7 parts of water. The charge was transferred to a Werner-Pfleiderer mixer and worked at 80 C. until a tough crumb formed. This crumb was then transferred to a rubber mill and homogenized to form a smooth sheet. This product was then, cured. at 130 C. for 30 minutes in a mold under pressure. It gave an elastomer of the following properties: tensile strength, 2170 lbs. per sq. in.; elongation at the break, 300%; linear swell in cold water after 4 days, 12%

Example 6 A polymeric glycol containing repeating units of the probable structure and having terminal OH groups was prepared by azeotropic distillation of the following charge: 244 parts thiodiglycol, 180 parts butane-1,4-diol, 100 parts toluene, parts p-toluene sulfonic acid. After removing 71 parts of water, the product was isolated and dried by the procedure of Example 1. The yield of polyglycol was 280 parts, having a hydroxyl number of 43. The molecular weight calculated from this was 2600.

100 parts of this glycol and 52 parts of toluene-2,4-diisocyanate were mixed and heated at 100 C. for 1 hour. The charge was then transferred to a Werner-Pfleiderer mixer and 0.8 part of pyridine and 5.4 parts of water were added. After a few minutes milling, a crumb formed which was transferred to a rubber mill and formed into a smooth sheet. This material was then cured by heating in a press at 130 C. for'30 minutes. The amber colored elastomer had the following properties: tensile strength at the break, 2200 lbs. per sq. in. elongation at the break, 100%.

Example 7 One mol of polyalkylene ether-thioether glycol (having a molecular weight of 2490, OH No. 45 and 16.2% sulfur and made by the procedure of Example 4 from 1 mol of thiodiglycol and 1 mol diethylene glycol) was stirred with 1.7 mols of hexamethylene diisocyanate at 120125 C. for 1 hour. The mass was cooled to about 95 C. and 0.37 mol of water was added and stirring was continued for 1-0 minutes. The-resulting gummy mass was spread on a waxed pan and heated in an oven at 105- 110 -C. for 2 hours. A rubbery mass resulted. This was milled on a rubber mill to a band and 0.9 part of piperidine per 100 parts of polymer was milled in to vstabilize the polymer.

Then 100 parts was sheeted out on a rubber mill and 5 parts of N,N'-bis(3-isocyanato-4-methylphenyl) urea was thoroughly milled in. A portion was put in a mold low-modulus elastomer was obtained.

. --Example8 One mol of the polyalkylene ether-thioether glycol of Example 7 was stirred with 2.1 mols of naphthalene-1,5- diisocyanate at 115 C. for 10 minutes when it became very viscous. 0.66 mol of water was then mixed in and the mass was transferred to a rubber mill and milled until uniform. There was then added 1.0 part of piperidine per 100 parts of polymer and the polymer was milled further tolstabilize it against precuring.

"100' parts of the stabilized polymer was milled on a rubber mill with 5 parts of N,N'-bis(3-isocyanato-4- methylphenyl) urea and a portion was placed in a mold and cured by heating in a press at 270 F. for 30 minutes. The resulting rubbery slab had a tensile strength of 1100 lbs. per sq. in., a modulus at300% elongation of 600 lbs. per sq. in., and an elongation at the break of 700%.

Examp leQT A mixture of 366 parts ofthiodiglycol,270 parts of 'tetramethylene glycol, 132 parts of benzene and 9 parts of p-toluene'sulfonic' acid was azeotropically distilled, the water layer being separated and the benzene being returned to the distillation. Approximately 106 parts of water layer contaminated with some glycol was separated. The benzene solution of the polyalkylene ether-thioether glycol was then boiled with 10% sodium carbonate solution, washed with water and finally freed from solvent and water by heating at 110C. under about 1 mm. pressure. There resulted 366 parts of polyether-thioether glycol with a hydroxyl number of 64.5 and a molecular weight of 1735.

86.8 parts ofthe above polyalkylene ether-thioether glycol and 11.6 parts of toluene-2,4-diisoeyanate were heated and mixed in a Werner-Pfleiderer mixer for 2 hours at 80 C. and then 2 hours at 130 C. The temperature was reduced to 100 C. and 1.83 parts of 2,4- tolylenediamine was added and mixing was continued for .10-minutes.' A soft, rubbery plastic resulted. This was cured by milling on a rubber millwith 4 parts of N,N-

bis(3-isocyanato-4-methylphenyl) urea per 100 parts of polymer until a homogeneous mass was formed and then curing in a mold at 134 C. for 30 minutes under pressure.- A resilient, rubbery slab was obtained. .It did .not freeze (or crystallize) on being held for, 2 weeks at isocyanate were heated and mixed in a Werner-Pfleiderer mixer at 110 C. for-2 hours. The mass was cooled *to 80C. Then 0.14 part of Water was added and mixing was continued at 80 C. for 30 minutes. 10 parts of toluene-2,4-diisocyanate was added and mixing was continued a further'2 hours at 80 C., after which 3.15 parts .of water was added and mixing was continued for 45 stabilize it.

-minutes while the temperature was increased to C.

100 parts of this polymer were milled on a rubber mill with 4 parts of N,N-bis(3-isocyanato-4-methylphenyl) urea and then cured in a mold under pressure for 30 minutes at 134 C. The resulting soft, rubbery slab was not frozen when kept at -20 C. for 2 weeks;

that is, it still showed characteristic rubbery properties at 7 Example 11 V A polyether-thioether glycol was made by azeon'opically distilling a mixture of 4.49 mols of thiodiglycol and 4.49 mols of propane-1,2-diol in parts of benzene -with 13.5 parts of p-toluene sulfonic acid monohydrate until about 80% of the theoretical amount of water had been distilled over, the benzene being returned to the reaction vessel. Then an additional 0.67 mol of thiodiglycol was added and the reaction completed. The crude ether was worked up in the same way as that of Example 9. There was obtained 667 parts of a polyether-thioether glycol having a molecular weight of 926 as determined by OH number. The sulfur content was 21.7%.

278 parts of the polyalkylene ether-thioether prepared above was mixed with 36 parts of toluene-2,4-diisocyanate and heated at 100 C. for 3 hours while agitating. The mass was cooled to 60 C. and an additional 36 parts of toluene-2,4-diisocyanate was added and stirring was continued for 18 hours, at 60 C. To the prepolymer at room temperature was then added 1325 parts of dry tetrahydrofuran and the mass was stirred until it was completely in solution. Then 18 parts of water was thoroughly stirred in and the solution was allowed to stand at room temperature for 136 hours for chain extension to take place. The tetrahydrofuran was then evaporated.

100 parts of the polymer was compounded on a rubber roll mill with parts of high abrasion furnace black, 8 parts of l,3-bis(3-isocyanato-p-tolyl) urea and 0.5 part of 2-mercaptobenzimidazole and then cured in a mold in a press at 134 C. for 30 minutes. After standing for 2 weeks the elastomer had the following properties at C.: tensile strength at the break, 2350 lbs, per sq. in; modulus at 300% elongation, 1730 lbs. per sq. in; elongation at the break, 370%.

Example 12 A tetramethylene ether-thiodiglycol polyether glycol was prepared by azeotropically distilling a mixture of 604 parts of thiodiglycol, 405 parts of 1,4-butanediol, 13.5 parts of p-toluene sulfonic acid monohydrate and 210 parts of benzene, separating the water and returning the benzene to the reaction vessel. Distillation was continued to a pot temperature of 168 C. and 174 parts of water had distilled over. The crude polyether-thioether was worked up as in Example 9 to yield 612 parts of a viscous liquid analyzing 20.1% sulfur and having a molecular weight of 2285 as determined by hydroxyl number.

228.5 parts of the polyether was then mixed with 36.3 parts of toluene-2,4-diisocyanate and stirred at 60 C. for 18 hours. Then 1120 parts of dry tetrahydrofuran was added to the cooled prepolymer and 17.3 parts of water was thoroughly stirred into solution. After standing for 66 hours for chain extension to take place, the solvent was evaporated.

100 parts of the polymer was compounded on a rubher roll mill with 10 parts of 1,3-bis(3-isocyanato-ptolyl) urea and cured in molds in a press at 134 C. for minutes. After standing for 14 days, the elastomer had the following properties at 25 C.: tensile strength at the break, 1150 lbs. per sq. in.; modulus at 300% elongation, 640 lbs. per sq. in.; elongation at the break, 670%.

When similarly compounded with 8 parts of 1,3 b-is- (3-isocyanato-p-tolyl) urea and cured, the elastomer did not freeze after 7 days at 20 C. and showed a T-50 value of -41 C. (A.S.T.M. test D-599-40T).

Example 13 A polyalkylene ether-thioether glycol of the general formula OH; HO- CHgCH2 S-OH2HOH2O azobisisobutyronitrile was added and the solution heated to 60 C. Then 343 parts of distilled mercaptoethanol was added while agitating over a period of 1 hour during which the temperature increased to about -85 C. After the addition was complete, stirring was continued 30 minutes at 8083 C. and then an additional 15 minutes at C.

The mass was then distilled, 554 parts of the mercaptoethanol-methallyl alcohol adduct being obtained at 128- 132 C. at a pressure of 1.21.5 mm. of mercury.

500 parts of this adduct was dissolved in 500 parts of dry xylene and 4.5 parts of concentrated sulfuric acid was added. The mixture was azeotropically distilled, the water being separated and the xylene returned to the reaction vessel. The temperature in the pot gradually rose from about C. .to about C. and 93 parts of water was distilled off. The solution was cooled to below 100 C. and 500 parts of water and 20 parts of phenyl-B-naphthylamine were added and the mass stirred. It was then heated to reflux for 2 hours. The water layer was discarded and the oil layer washed with warm water until it was free of acid. The oil layer was dried over anhydrous sodium sulfate and filtered. There was then added 15 parts of lime and 15 parts of activated charcoal with agitation and the solution filtered again. The xylene was then removed by distillation under vacuum. 421 parts of a colorless, polyether-thioether glycol was obtained which had a molecular weight of 1450 by hydroxyl number determination. 30

149 parts of the polyethenthioether glycol containing 0.04 mol percent water was stirred with 26.8 parts of toluene-2,4-diisocyanate at 60 C. for 18 hours. The cooled prepolymer was then dissolved in 500 pants of dry tetrahydrofuran and 5.4 parts of water was thoroughly stirred in. After standing at room temperature for 3 days, the tetrahydrofuran was evaporated.

100 parts of the elastomer was compounded on a rubber mill with 10 parts of l,34bis(3-isocyanato-patolyl) urea and cured in molds in a press at 134 C. for 30 minutes. The soft, resilient 'elastom'e'r had a T-50-value of 30 C. and showed a weight gain'of only 0.71% after'immersion in water at 30 C. for 7 days and 0.68% after similar exposure to octane.

The present invention represents a distinct advantage in the art since the elastomers herein disclosed have good tensile strength, elasticity, and further have the advantage that they may be fabricated into sheets, rods, tubings and the like. They also retain their elastomeric character at low temperatures. The products of the in- ,vention have good resistance to swelling by water and aliphatic hydrocarbon solvents.

Products fabricated from the herein disclosed polymers are particularly useful in preparing articles and appliances used in the automotive, aeronautical and petroleum industries, where pipelines, gaskets, and other objects prepared from such polymers are in constant contact with hydrocarbon solvents and oils. The products may also be used for coating fabrics, molding solid articles, forming sheets andas abrasionresistant coating compositions. When used for coating, the isocyanate-terminated polymer may be dissolved in a volatile solvent and spread over the surface. After the solvent has evaporated, the polymer may be heated to cure it or it may be allowed to cure slowly at room temperature. If water is to be used as the chain extending agent, the moisture of the air is suitable, particularly under high relative humidity conditions. Chain extending agents and curing agents may be incorporated in the coating composition as desired. Also, pigments,

plasticizers, and other modifying agents may be moorporated in the composition.

tended to be limited except as indicated in the appended claims.

What is claimed is: M 4 allcylene etherthioether glycol having a molecular weight 1. A polymer consisting essentially of structural units of a tleast 750, said glycol having a ratio of ether oxygen having the formula 7 I I p p atoms to sulfur atoms of from about 1:1 to 15:1; B is a r ii i x l I m NH-BNHCO-GO --NHBNHQ'HNBNH' L 1.. /m l wherein OGO is a bivalent radical resulting from 10 bivalent organic radical, said radical being inert to isocyremoval of the terminal hydrogen atoms from a polyanate groups; and n is an integer greater than zero. alkylene .etherthio'ether glycol having a molecular weight '9. The polymer of claim 8 wherein the bivalent orof at least 750, said glycol having a ratio of ether oxygen ganic radical B is a 2,4-tolylene radical. atoms to sulfur atoms of from about 1:1 to :1; B is 10,. The process for preparing a polymer of claim 8 a bivalent organic radical, said radical being inert to iso- 15 which comprises reacting a polyalkylene ether-thioether cyanate groups; Q is a radical selected from the group glycol having a molecular weight of at least 750, said consisting of a carbonyl radical and a diacyl radica1; n glycol having a ratio of ether oxygen atoms to sulfur is an integer greater t112111 Zero; and m is an Integer 1-11- atoms of from about 1:1 to 15:1, with a molar excess cluding zero; each of the said structural units being conof an organic diisocyanate.

nected to the next by a'radical Q, having the significance 2O 11. The process of preparing a polymer of claim 1 defined; the Overall ratio of the number 05 B to G-- which comprises reacting a polyalkylene ether-thioether radicals in the polymer being between 1.1:1 and 12:1 glycol having a molecular weight of at least 750, said with at least 35% of the total weight of the polymer being glycol having a ratio of ether oxygen atoms to sulfur the bivalent radicals O-GO. atoms of from about 1:1 to 15:1, with a molar excess 2. The polymer of claim 1 wherein the bivalent radical of an organic diisocyanate-and further reacting the re- OGO results from removal of the terminal hydrogen suiting isocyanate-terminated polymer with a chain exatoms f a p y y ether-thioether y said tending agent having a plurality of active hydrogen atoms glycol being the Condensation Prddllct 0f i igly olan capable of reacting with isocyanates, no more than two butane-lfldiol and having a ratio f ether yg n atoms atoms in the molecule of the said chainextending agent to sulfur atoms of from about 1:1 to 15:1. having active hydrogen attached thereto, said chain ex- 3. The polymer of claim 1 wherein the bivalent organic tending agent being elect d from the group consisting radical B is an arylene radical. of water, hydrogen sulfide and organic compounds con- The P y of claim 2 wherein B is a Ylene taining two functional groups in the molecule to which radical. are attached active hydrogen atoms. 7

The P 3 of claim 4 wherein Q a carbonyl 12. The process of claim 11 wherein the organic digroup. isocyanate is an arylene diisocyanate.

The P y of claim 4 wherein Q is the y 13. The process of claim 12 wherein the chain extendradical ing agent is water. 7

O Q i 4 14. The process of claim 12 wherein the chain extendlI l 7 mg agent 1s an organic diamme.

wherein NH NH an organic radical resulting References Cited in the file of this patent 2522,11 1 igeimovafil= of terminal hydrogen atoms from an or- UNITED STATES PATENTS a 7. A cured elastomer obtained by reacting the poly- 2,216,044 Patrlqk P 1940 may of claim 1 with an organic polyisocyanate. 2,513,245 Moms et all 1950 8 A olymer having the Fettes O 0 2,692,873 Langerak et a1. Oct. 26, 1954 r f H H 2,692,874 Langerak Oct. 26, 195 Q BNGO 2,853,472 Schroeder ct a1. Sept. 23, 1958 wherein O-G-O is a bivalent radical resulting from FOREIGN PATENTS removal of the terminal hydrogen atoms from a poly- 894,134 France Dec. 14, 1944 

1. A POLYMER CONSISTING ESSENTIALLY OF STRUCTURAL UNITS HAVING THE FORMULA 